Device for inspecting filled and closed receptacles

ABSTRACT

A device for inspecting filled and sealed containers consisting of a first carousel in which the containers to be inspected can be rotated about their longitudinal axis so that the contents in the containers begin to rotate with sufficient speed to stir up any foreign bodies that may be present from the bottom of the container and consisting of a second carousel following the first carousel in the direction of transport for bottom-free transport of the containers, at least one inspection device which operates by the dark field method being provided for detection of light scattering foreign bodies in the contents, whereby the two carousels are arranged side by side with their partial circles in tangent so that the containers can be transferred from the first carousel directly to the second carousel.

This invention relates to a device for inspecting filled and sealedcontainers according to the preamble of claim 1.

WO 94/08230 describes a method and a device for inspecting transparentcontainers and their liquid contents. The disclosed device has twocontinuously drivable carousels; the containers that are to beinspected, e.g., filled beverage bottles, pass through these carouselsone after the other. In the first carousel as seen in the direction ofconveyance, the containers are first rotated once completely about theirvertical axis at a low rate of rotation, during which the side wall isobserved by a camera for detecting damage or other defects in thecontainer itself. Following this, the rate of rotation is initiallyincreased to induce rotation of the liquid with the goal of creatingturbulence to churn up any foreign bodies present on the bottom of thecontainer. Even before leaving the first carousel, the rotationalmovement of the containers is stopped so they can then be transferredvia a first star wheel, a pitch lag screw and a second star wheel to thesecond carousel, where the containers are inspected by a bright fieldmethod and also by a dark field method by cameras that move with thecarousels but without any rotation of the containers themselves abouttheir vertical axis in order to detect any foreign bodies in the fillingof the containers (suspended materials, particles, etc.).

One disadvantage is that a separate, independently controllable electricmotor drive is provided for each container in the first carousel, butthis is very high expensive in terms of the drive technology.

Another disadvantage is that the transfer zone from the first carouselto the second turns out to be very long due to the use of the twotransfer star wheels with the screw connected in between; this resultsin a relatively great deceleration of the rotating liquid in thecontainers even before reaching the second carousel, where the actualforeign body detection in the liquid is then performed. However, thereliability of this inspection method is inadequate at low throughputrates and/or with heavier foreign body particles, in particulartransparent bodies, which can be detected reliably only when inmovement.

In addition, the conveyance elements mentioned above, which arenecessary for the intermediate transfer, depend on the format of thecontainers to be inspected and must therefore be switched to anothertype of container with each conversion of the inspection machine [fromone product to another]. This is also true of the intake star wheel ofthe first carousel and the output star wheel of the second carousel.Furthermore, the guide curves arranged between the star wheels are alsointerchangeable parts that depend on the format.

Because of the great center-to-center distance between the twocarousels, the known inspection machine also takes up a relatively largeamount of space.

Based on this prior art, the object of this invention is to provide adevice for inspecting filled and sealed containers which will permit acompact design with increased reliability of detection at a lower cost.

This object is achieved by the characterizing features of Claim 1.

Due to the tangent arrangement of the carousels, a direct transfer ofthe containers from the first carousel to the second carousel without abypass is possible, which eliminates not only transfer elements thatdepend on format but also makes it possible for the containers to beinspected immediately for any foreign bodies that might be present inthe liquid after rotational acceleration of their liquid contentswithout any mentionable loss of time, so that even relatively heavylight-scattering foreign bodies can also be detected reliably while inmotion before they settle to the bottom of the container even atrelatively low throughput rates.

Other advantageous embodiments of this invention are the object of theremaining subclaims.

A preferred exemplary embodiment of this invention is described below onthe basis of the figures, which show:

FIG. 1 inspection machine in a highly schematic view from above and

FIG. 2 a vertical partial section through the outer peripheral area of afirst carousel of the inspection machine in FIG. 1.

The inspection machine shown schematically in FIG. 1 is set up speciallyfor inspecting filled and sealed beverage bottles made of a transparentor semitransparent material. The bottles F to be inspected are sentcontinuously from an upstream bottle filling and sealing machine, forexample, via a feeder conveyor belt 1 to a feeder star wheel 2, wherethey pass through a stationary intake inspection station 9 (at thelatest before being transferred by the feeder star wheel 2) which checksthem for the presence of a seal and may optionally also check thefilling level. To prevent soiling of the inspection units due tospillage of liquid from unsealed bottles, such bottles are not grippedby the intake star wheel 2 and they pass by it in the tangentialdirection in the direction of a downstream collecting point. The sameprocedure is followed with overfilled or underfilled bottles.

The intake star wheel 2, which can be driven continuouslycounterclockwise has on its periphery a plurality of selectivelycontrollable gripper clamps arranged at a uniform machine pitch spacing,said grippers being adaptable to different bottle diameters for grippingthe bottles in the body area and optionally also in the head and/or neckarea. During the transfer from the feeder conveyor belt 1 to a firstcarousel 3, which follows in the circumferential direction, the bottlesare first conveyed forward with a bottom clearance over a stationarybottom blow-off device 10 for removing soap suds or the like and adownstream bottom monitoring station 11 that can be operated by thebright field method for detecting soiling or damage to the bottom of thebottle itself as well as heavy foreign particles that cannot beresuspended by rotating the bottle.

The intake star wheel 2 may be designed, for example, according toEuropean Patent 0 726 216 B1 and European Patent 0 743 267 B1; thebottom blow-off device 10 may be designed according to German UtilityModel 94 01 926 U1, and bottom inspection station 11 may be designedaccording to German Patent Application 101 33 104. The disclosurecontent of these cited patent applications is explicitly included here.

At the point of contact of the partial circles of the intake star wheel2 and the first carousel 3 which is revolving counterclockwise, thebottles F with their bottom surfaces are transferred to rotating table12, which is mounted to rotate about a vertical axis in the carousel,and then the bottles are held in an axial grip so that they can rotate,as is known per se from the prior art which forms the generic type. Inthe remaining course, the bottles which are upright on the rotatingtables 12 are first set in rotation continuously about their verticalaxis and accelerated in passing by the first revolving sector A of thecarousel 3 and then they pass through the revolving sector B at adefined maximum rotational speed, followed by a revolving sector C forcontinuous deceleration of the bottle rotation approximately to astandstill.

To create the aforementioned rotational movements of the rotating tables12, each rotating table has a pinion 13 which is mounted to rotatefreely at the bottom on its shaft 22 and meshes with the internalgearing of a toothed gear rim 14 which has internal and external gearingand is supported via a ball bearing slewing rim on the frame plate G ofthe machine. This toothed gear rim 14 can be driven counterclockwise andin the opposite direction from carousel 3 by a variable speed drive(electric motor or the like) and is controlled by a driving gear wheel15 that meshes with its exterior gearing. This opposing rotation permitsa sufficiently high rotation of the rotating tables. The shafts 22 inpassing through the aforementioned revolving sectors A, B, C can beconnected more or less greatly to their respective pinion, and in theremaining revolving sector of the carousel 3, they can be connected tothe carousel itself via controllable magnetic couplings which aredescribed in greater detail with reference to FIG. 2.

At least one side wall camera 16 is situated on the periphery of thefirst carousel 3, and diametrically opposite that on the outer side ofthe carousel 3 there is a side wall luminescent screen 17. Thisarrangement is used for bright field inspection in transmitted light,which makes it possible to detect damage and/or soiling that causesopacity or opaque suspended particles or the like set in motion by therotating motion of the liquid in the bottles.

The end area of the rotating sector C of the first carousel 3 is tangentto a second carousel 4 which has—just like the intake star wheel 2—aplurality of selectively controllable grippers for gripping the bottlesin the body area and optionally also in the head and/or neck areasituated on its periphery and arranged so they are offset with themachine pitch spacing. Thus the bottles F can be gripped at the commonpoint of contact with the first carousel 3 and transferred with a bottomclearance counterclockwise in the direction of the following sortingstar wheel 5, whereby on the way there the bottles are subjected to aforeign body detection in the dark field method with whichlight-scattering foreign bodies, in particular transparent splinters ofglass, can be detected.

To this end, equidistant luminescent screens 18 and 19 which are adaptedto the curvature of the path are arranged in stationary positions onboth sides of the curved peripheral :path of the bottles F, so that thebottles can pass freely between the screens and be illuminated over thelargest possible area from the sides. Due to the simultaneous bilateraltunnel-like illumination, a very high light induction into the bottlescan be achieved, which is advantageous in particular in the case ofopaque or dark liquids such as beer-containing yeast or colas.Luminescent screens 18 and 19 may preferably be equipped with aplurality of LEDs which can be operated in a pulsating manner by alighting control device.

Furthermore, the second carousel 4 is equipped with cameras 20 arrangedbeneath its grippers (not shown), e.g., one camera per gripper wherebythe cameras revolve in positional synchronization with the grippers andare able to image the bottom of the illuminated bottles, optionallyusing deflector mirrors (not shown here) positioned beneath the bottlesat an oblique angle. This arrangement achieves a dark field lighting inwhich the light scattering defects and/or foreign bodies appear as lightspots or zones in an otherwise dark image.

Alternatively, a stationary arrangement of one or more cameras wouldalso be conceivable. By simultaneous triggering of the cameras 20 torecord the image and the LEDs of the luminescent screens 18 and 19, thetriggering that would otherwise be necessary may be omitted.Furthermore, a modification in which one camera can always detect andimage several bottle bottoms simultaneously through a suitable mirrorarrangement is also possible.

The sorting star wheel 5 which is also equipped with selectivelycontrollable grippers (not shown) is capable of delivering the inspectedbottles to various conveyor belts as a function of the test results bybottom inspection station 11 side wall camera 16 and cameras 20 whichobserve the bottles F through the bottom. Thus, for example, the bottleswithout a distance between them may leave the inspection machine via thedischarge conveyor belt labeled as 6 while bottles having defects can bediverted to either discharge belts 7 or 8, depending on the type ofdefect detected.

FIG. 2 shows in detail the drive for the rotating tables 12 arranged onthe first carousel 3. The rotating tables 12 are each arranged fixedlyon the upper end of shafts 22 mounted vertically in carousel 3so theycan rotate on a common partial circle. On each shaft 22, a magnetic ring23 is guided so that it is axially displaceable up and down and engagesin a rotationally fixed manner with its shaft 22 for transmission oftorque. Furthermore, a hysteresis ring 27 is arranged in a rotationallyfixed manner, coaxially with each shaft 22 in the carousel 3, the insidediameter of this hysteresis ring being slightly larger than the outsidediameter of the magnetic ring 23. A second hysteresis ring 25 having aninside diameter which slightly exceeds the outside diameter of themagnetic ring 23 is mounted on the shaft 22 so that it is coaxial andfreely rotatable; it is arranged with an axial distance beneath theaforementioned first hysteresis ring 27 so that it is rotationally fixedwith each pinion 13, which engages with the toothed rim 14. The axialdistance between the two hysteresis rings 25 and 27 correspondsapproximately to the height of the magnetic ring 23 which is equippedwith several oppositely polarized permanent magnets arranged inalternation on the circumference, at least on its upper and lower edges.The hysteresis rings are made of a material having a high permeabilitysuch as soft iron.

Each of the magnetic rings 23 is movable up and down longitudinallyalong the shaft 22 by means of an activating device not shown here,e.g., a mechanical cam control and can thus form a magnetic couplingoptionally with: the drivable lower hysteresis ring 25 or the upperrotationally fixed hysteresis ring 27, whereby the transmittable torqueis variable via the depth of immersion, i.e., the axial coverage of themagnetic ring 23 with the respective hysteresis ring. The controllablecoverage permits a simple means of controlling the acceleration torqueand/or the braking torque which can be transmitted to a bottle F in theindividual peripheral sectors of the carousel 3. In this way, eachrotating table 12 can be acted upon by torque with an accelerating ordecelerating effect with practically no wear during a revolution withthe carousel in the correct position for the instantaneous rotationalposition without any electrotechnical complexity and independently ofthe neighboring rotating tables.

Therefore, individual electric motor drives are not necessary for eachrotating table. The drive for all rotating tables 12 may be derivedeasily via the toothed rim 14 and the driving gear wheel 15 from thecentral machine drive alone, so that synchronization of speed androtational position is automatically ensured for all the remainingprocess sequences of the inspection machine.

In deviation from this, however, a separate variable-speed motor driveindependent of the machine drive may also be used, acting upon drivewheel 15.

1. A device for inspecting filled and sealed containers, comprising afirst carousel (3) in which the containers (F) that are to be tested canbe rotated about their longitudinal axis so that the contents in thecontainers begin to rotate at a sufficient speed to cause any foreignbodies that might be present to be stirred up from the bottom of thevessel, and a second carousel (4) which follows the first carousel (3)in the direction of conveyance for conveying containers with a bottomclearance, the second carousel being assigned at least one inspectiondevice (20) that operates by the dark field method for detecting lightscattering foreign bodies in the container contents, and the first andsecond carousels (3, 4) are arranged side by side with their partialcircles tangent so that the containers (F) can be transferred directlyfrom the first carousel (3) to the second carousel (4).
 2. The deviceaccording to claim 1, and a star wheel (2) which transports thecontainers with a bottom clearance is arranged upstream from the firstcarousel (3) as seen in the direction of transport and is assigned oneof at least one bottom blow-off device (10) and a bottom inspectionstation (11) that operates by the bright field method.
 3. The deviceaccording to claim 1, and an intake inspection (9) for one of checkingthe filling levels and the container closures is provided one ofupstream from the star wheel (2) and the first carousel (3).
 4. Thedevice according to claim 3, wherein unsealed containers are nottransferred from the star wheel (2) or the first carousel (3).
 5. Thedevice according to claim 1, wherein the first carousel (3) has multipledrivable rotating tables (12) on a partial circle, said disks beingengageable or disengageable in a frictionally locked manner viacontrollable magnetic couplings (23, 27) with a drive element that allthe rotating tables have in common (14,15).
 6. The device according toclaim 5, wherein the magnetic couplings (23, 27) are hysteresis clutcheswith a variable torque.
 7. The device according to claim 1, andluminescent screens (18, 19) that are diametrically opposed and areadapted to the curvature of the path so they are equidistant areprovided in at least some sections on both sides of the peripheral pathof the second carousel (4), simultaneously lighting up the containers(F) laterally at the same time while the bottom is being photographed.8. The device according to claim 7, wherein the luminescent screens (18,19) are equipped with LEDs that can be triggered in a pulsating patternand are always triggerable simultaneously with a photograph of thebottom.